HTML and XHTML documents that include images that cannot be described in a short text alternative.
This technique relates to:
Some older assistive technologies do not support the longdesc
attribute.
The objective of this technique is to provide information in a file designated by the
longdesc
attribute when a short text alternative does not adequately convey the function
or information provided in the image. The longdesc
attribute is a URI, the target of
which contains a long description of the non-text content.
<p><img src="chart.gif" alt="a complex chart" longdesc="chartdesc.html"/></p>
Check that a longdesc attribute exists.
Check that the link in the longdesc attribute is valid
Check that the long description describes the original non-text content associated with it.
#1 through #3 are all true